Introduction
Carbon nanotubes (CNTs) have continuously attracted much
interest because of their outstanding mechanical, chemical and
electric properties [1]. However, high agglomeration tendency
caused by strong inherent attractive van der Waals interaction
makes a difficulty in their applications [2–5]. As a result, carbon
nanotubes are easily aggregated and exist as bundles in their native
state. To overcome the problem and improve the processibilty, CNTs
have been treated with strong acids or some surfactants [6,7]. The
applications of multi-walled carbon nanotubes (MWNTs) are also
growing in diverse fields because it can be produced at relatively
low cost. Nanoparticles of metal, metal oxide, and semiconductor
are also of great interest due to their potential applications as
microelectronics, optoelectronics, catalysis, and information storage
[8–10].
Combining two characteristic nanostructured materials is
expected to provide a versatile building block for the construction
of modern nanodevices. For instance, the decoration of CNTs with
some nanoparticles expands their applications from CNT-assisted